Perhaps no other product demonstrates more clearly the strange behavior at nanoscales than something called Osorb. An accident of chemistry, the swellable glass material was intended to react with trace molecules of explosives, which would have made it a valuable security tool at places like airports. But something very weird happened in the development process, recalled Paul Edmiston, Osorb's designer and a chemistry professor at the College of Wooster in Wooster, Ohio. He and some graduate students were trying to design nanostructured silica--glass--to change colors in the presence of vapors.
"We serendipitously discovered a formulation by which the nanoparticles we were assembling into this porous glass film had become flexible. Instead of being a solid, they had the ability to swell," he said. "Yeah, we had the color change, but it soaked up the entire volume of the test solution. We put more on and it sucked up more. It just expanded." (Watch a video of that here
Edmiston was intrigued, but shelved the product in search of something that would satisfy the need for explosives detection, which was the point of his research grant. "It was like, 'Well, that's not going to work on a boarding pass,'" he recalled with a laugh. A graduate student resurrected it later and the team realized the material had some very interesting properties--especially its complete lack of reaction to water. Molecules can pass through the empty space between the nanosize silica, but water doesn't, Edmiston said. This makes it extremely useful for water cleanup. The swellable glass, now named Osorb and marketed commercially by a spinoff called ABS Materials, can soak up oil and other organic material, and you can wring it out afterward and use it again.
How does glass swell? "Chemically, it's halfway between the window pane glass in your house, and the caulk that's around your sink," Edmiston explained. "Those type of ingredients, from a chemical level, build them up into a architecture that has the ability to expand and contract."
Osorb is already being used in places like parking lots, where it can absorb oil from leaky cars and prevent it from washing into bodies of water. It can be decorated with other material, like iron, to capture chemicals like phosphate. Edmiston has a new grant to study how this works, because he's not sure if there's a biological factor at play. One other weird thing: As it swells, it generates a remarkable amount of force, Edmiston said. It can lift 60,000 times its own weight. "If you had a coffee can of it, that's enough to lift a car," he said. "You might imagine we discovered that the hard way. We've broken a number of things in the lab because you just cannot contain it."